xnu-1486.2.11.tar.gz

[apple/xnu.git] / bsd / hfs / hfs_catalog.c

diff --git a/bsd/hfs/hfs_catalog.c b/bsd/hfs/hfs_catalog.c
index 5e7e13d99e4baad1fa2b396db06487084e8021fd..bb48eda7fb1cd4b131c212a52bb400f590724a57 100644 (file)
--- a/bsd/hfs/hfs_catalog.c
+++ b/bsd/hfs/hfs_catalog.c
@@ -2669,6 +2669,27 @@ getdirentries_callback(const CatalogKey *ckp, const CatalogRecord *crp,
 
        /* We're done when parent directory changes */
        if (state->cbs_parentID != curID) {
+               /*
+                * If the parent ID is different from curID this means we've hit
+                * the EOF for the directory.  To help future callers, we mark
+                * the cbs_eof boolean.  However, we should only mark the EOF 
+                * boolean if we're about to return from this function. 
+                *
+                * This is because this callback function does its own uiomove
+                * to get the data to userspace.  If we set the boolean before determining
+                * whether or not the current entry has enough room to write its
+                * data to userland, we could fool the callers of this catalog function
+                * into thinking they've hit EOF earlier than they really would have.
+                * In that case, we'd know that we have more entries to process and
+                * send to userland, but we didn't have enough room.  
+                * 
+                * To be safe, we mark cbs_eof here ONLY for the cases where we know we're 
+                * about to return and won't write any new data back
+                * to userland.  In the stop_after_pack case, we'll set this boolean
+                * regardless, so it's slightly safer to let that logic mark the boolean,
+                * especially since it's closer to the return of this function.
+                */              
+
                if (state->cbs_extended) {
                        /* The last record has not been returned yet, so we 
                         * want to stop after packing the last item 
@@ -2676,10 +2697,12 @@ getdirentries_callback(const CatalogKey *ckp, const CatalogRecord *crp,
                        if (state->cbs_hasprevdirentry) { 
                                stop_after_pack = true;
                        } else {
+                               state->cbs_eof = true;
                                state->cbs_result = ENOENT;
                                return (0);     /* stop */
                        }                               
                } else {
+                       state->cbs_eof = true;
                        state->cbs_result = ENOENT;
                        return (0);     /* stop */
                }
@@ -3057,6 +3080,12 @@ cat_getdirentries(struct hfsmount *hfsmp, int entrycnt, directoryhint_t *dirhint
        state.cbs_nlinks = 0;
        state.cbs_maxlinks = maxlinks;
        state.cbs_linkinfo = (linkinfo_t *)((char *)buffer + MAXPATHLEN);
+       /*
+        * We need to set cbs_eof to false regardless of whether or not the
+        * control flow is actually in the extended case, since we use this
+        * field to track whether or not we've returned EOF from the iterator function.
+        */
+       state.cbs_eof = false;
 
        iterator = (BTreeIterator *) ((char *)state.cbs_linkinfo + (maxlinks * sizeof(linkinfo_t)));
        key = (CatalogKey *)&iterator->key;
@@ -3065,7 +3094,6 @@ cat_getdirentries(struct hfsmount *hfsmp, int entrycnt, directoryhint_t *dirhint
        if (extended) {
                state.cbs_direntry = (struct direntry *)((char *)iterator + sizeof(BTreeIterator));
                state.cbs_prevdirentry = state.cbs_direntry + 1;
-               state.cbs_eof = false;
        }
        /*
         * Attempt to build a key from cached filename
@@ -3186,8 +3214,14 @@ cat_getdirentries(struct hfsmount *hfsmp, int entrycnt, directoryhint_t *dirhint
        /* Note that state.cbs_index is still valid on errors */
        *items = state.cbs_index - index;
        index = state.cbs_index;
-
+       
+       /*
+        * Also note that cbs_eof is set in all cases if we ever hit EOF
+        * during the enumeration by the catalog callback.  Mark the directory's hint
+        * descriptor as having hit EOF.
+        */
        if (state.cbs_eof) {
+               dirhint->dh_desc.cd_flags |= CD_EOF;
                *eofflag = 1;
        }